Air return scoop for air handling luminaires

ABSTRACT

An air handling luminaire including a troffer and a light transmissive air handling door assembly which includes air return passages in opposite ends of the door assembly constructed and arranged to direct air returning through the passages away from the lamp cavity toward the side walls of the troffer housing to thereby completely exclude light from exiting from the fixture through the air return passages. The air return passages further having included therein a variably positioned dampening mechanism to control the volume of air returning through the air return passages.

t teg; ato Johnson e 1541 AIR RETURN scoo Eon AIR HANDLING LUMINAIRES [72] Inventors: 'James C. Johnson, Arlington, Tex.; Winfried Neider-Westermann, Vicksburg,

Miss.

[73] Assignee: Westinghouse Electric Corporation, Pittsburgh,Pa. 22 Filed: Feb.9, 1970 21 Appl.No.: 9,563

[52 U.S. c1. .,98/40DL, 137/46, 240/9 A, 240 47 [51 1111.01. ..F2lv29/00 [58] FieldofSearch ..98/40D,4ODL,41;240/47; I 292/265; 137/46 [56] References Cited UNITED STATES PATENTS 3,555,267 1/1971 Sutier ..98/40 DLX 3,375,773 4/1968' Wotowiecetal. .....98/40DL 3,292,522 12/1966 Shur.., ..'....'....98/41 X 11 1 3,668,998 1451 June 13, 1972 Quin et a1. ..98/40 DL X 3,103,157 9/1963 Quin ..98/40 DL 3,220,332 1 1/1965 Straub ..98/40 DL 2,105,735 1/1938 Hodge.... ....292/26$ X 2,996,325 8/1961 Chenel .292/265 Primary Examiner-William F. O'Dea Assistant Examiner-P. D. Ferguson Attorney-A. T. Stratton, W. D. Palmer and Blair R. Studebaker 5 ABSTRACT An air handling luminaire including a trofier and a light transmissive air handling door assembly which includes air return passages in opposite ends of the door assembly constructed and arranged to direct air returning through the passages away from the lamp cavity toward the side walls of the troffer housing to thereby completely exclude light from exiting from the fixture through the air return passages. The air return passages further having included therein a variably positioned dampening mechanism to control the volume of air returning through the air return passages.

2 Claims, 7 Drawing Figures PATENTEBJUH 13 1912 SHEET 1 OF 2 jFIGI INVENTORS I6 FIG. 3

WITNE Es mw m 9 m@ N m m a W w A e m .w J I N d .w .n A .m i W be increased. A smoothly contoured BACKGROUND OF THE INVENTION This invention relates to air handling luminaires and more particularly to an air handling luminaire of the floating door" type wherein the air return channel or passage is located in the door frame.

Air handling luminaires having an air return feature are designed for thepurpose of drawing air from the occupied space or room through the lamp cavity of the fixture and into the plenum space of the building which lies between the ceiling of one room andthe floor of the room above. Many alternative schemes have been designed which are intended to permit air to enter the fixture through an air return passage and which will also prevent Iight from the lamps from escaping through the air return passage. These efforts to prevent light from exiting through the air entrance mechanisms have met with varying degrees of success. Some configurations employed to prevent the escape of light cause excessive air turbulence and consequently generate undesirable noise while in addition create an undesirably high static pressure drop across the fixture. It is important that the static pressure drop across the fixture be kept as low as possible since the higher the static pressure drop the larger the pressure differential which has to be developed in order to pull air through the fixture. A large static pressure drop in the plenum space is undesirable for the reason that there is a tendency for the ceiling tiles to be lifted causing the ceiling to leak air which then requires that fan horse power, duct sizes and operating costs of the system must air return passage helps significantly in reducing the static pressure drop required across the fixture. U.S. Pat. No. 3,375,773 to J. P. Wotowiec et al. for an Air Handling Light Fixture is illustrative of a substantial advance in the art of providing a smoothly contoured air return passage.

In addition to providing a smoothly contoured air return passage for the return of air through a lighting fixture the air return passage should also prevent light from the lamps within the fixture from being seen through the air return passage entrance slots and also should direct the air toward that portion of the fixture that generates the greatest amount of heat. In the fluorescent type lighting fixture to which this invention is directed the greatestamount of heat is generated at the ends of the lamps and at the location of the lamp ballast components. When the air return passage opens into the lamp cavity toward the center thereof light reflected from the back of the'fixture refractor or shielding media may easily enter and be reflected out of the air return passage unless that passage describes an exceedingly tortuous passage for the air flowing therethrough which, as described above, is undesirable because of the pressure differential created by such a tortuous ath. p When light is permitted by the lighting fixture to exit through the air return passage the aesthetic value of the fixture is also diminished significantly. The aesthetic value of the floating door effect which may be provided in a fixture having a continuous air space between the side runners and the door to effectively provide a frame on the four sides of the door is greatly diminished when light can be seen at the air entrance or air return slots. It has also been found that when the air return mechanism overlies the refractor or shielding media it can produce a shadow on the refractor which also has a deleterious affect on the appearance of the lighting fixture.

, With the increased use of U-bent fluorescent lamps, whereinfor purposes of cost reduction and efficiency the ballast equipment is best located at the end of the fixture into which the lamps are mounted, it becomes even more desirable to direct all return air toward the side wall to thereby direct the cooling air flow to the place where it will do the most good in removing heat from the fixture. Copending application Ser. No. 808,873, filed Mar. 20, 1969 for Integral Ballast, Lamp Holder Support and Wireway by James C. Johnson and William R. Ergle, Jr., owned by the assignee of this application, is

illustrative of the change in fixture design necessitated by the increased use of the U-bent type fluorescent lamps. In this type luminaire the ballast components as well as both ends of the lamp are located at one end of the lighting fixture and in order to produce a maximum cooling effect on these components it is desirable that the air retuming through the fixture be directed toward the end wall area of that fixture.

SUMMARY OF THE INVENTION Many of the above described inadequacies of the prior art are obviated through the present invention by providing in an air handling luminaire, which includes a trofier comprising a top wall and downwardly directed side and end walls and door means closing ofi the bottom of said tro'fi'er; air handling means in the door frame which includes a return passage having an outwardly directed, curved, air return scoop constructed and arranged to shield light emanating from the light source within the trofier from said passage, and which also includes air flow control means to'provide for the variable dampening of air returning through said passage.

BRIEF DESCRIPTION OF THE DRAWINGS Many of the attendant advantages of the present invention will become more readily apparent and better understood as the following detailed description of exemplary embodiments of the invention are considered in connection with the accompanying drawing, in which:

FIG. 1 is a bottom plan or room view of an air handling luminaire of the present invention;

FIG. 2 is a sectional view with portions thereof broken away taken along the line II-II of FIG. 1;

FIG. 3 is an expanded sectionalview of the lower left hand corner of FIG. 2;

FIG. 4 is a partial side elevation taken along the line IVIV of FIG. 3;

FIG. 5 is a sectional view similar to FIG. 3 illustrating an alternative embodiment of the present invention; FIG. 6 is a sectional view similar to FIG. 5 illustrating another position of the damper of the embodiment of FIG. 5; and

FIG. 7 is an isometric view ment of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The bottom plan view of FIG. 1 represents a view of the lighting fixture of this invention as v'iewedfrom the room or space from which air will be returned through the fixture. As illustrated in FIGS. 1 and 2 the luminaire is supported within the ceiling by the ceiling runners 12 which are conventionally an inverted T-channel and provides the luminaire with the appearance of being suspended or floating between the channels due to the air handling slots 14 and 15 which surround the visible portion of the door frame 16 which in turn retains the refractor or shielding media 18. As will be apparent from FIG. 1 the luminaire or more particularly the luminaire door appears to float in the opening defined by the ceiling runners because of the channels or slots 14 and 15 which entirely surrounds the door frame 16. The air handling slots 14 along the sides of the fixture serve to facilitate the introduction of conditioned air into the space or room while the air handling slots 15 at the ends of the door frame serve to facilitate the handling of air return through the fixture.

The luminaire generally designated 10 includes a top member 19 and downwardly directed end walls 20 and side walls 22 which form, in conjunction with the door defined by the door frame 16 and refractor 18 andenclosure 24 which houses conventional lamp holders 26 which are employed for mounting the heat generating light sources or more particu- Early fluorescent lamps 28.

As best illustrated in FIG. 3 the door frame member 16 on the ends of the luminaire have an upstanding leg 30 which has an intermediate cutout portion 31 on its inner surface forming partly in section of the embodia slot which serves to retain the light transmitting refractor or shield media 18. An inverted L-shaped member 32 is secured to the top of upstanding leg 30 of the door frame 16 by means of a plurality of bolts 34. The bolts 34 also serve to secure a curved duct member 36 to the door frame 16. The curved duct 36 overlies a slot 38 in the inverted L-shaped member 32 which slot serves as an opening into the air return passage defined by the curved duct member 36.

Return air entering the opening 15 traverses the chamber defined by upright member 30 and the L-shaped member 32 is drawn through the slot 38 in the L-shaped member 32 and is caused, by the curved duct member 36, to flow through passage 37 and be directed toward the end wall 20 and into the lamp cavity 24.

As can best be seen in FIG. 7 the curved duct or scoop member 36 is provided with an elongated slot or socket 39 which is employed to secure for rotation a vane or damper 40 which may be employed to control the volume of air flowing through the air return passage. The vane or damper 40 has at one end a cylindrically shaped projection of a diameter which will permit it to slide within the socket or channel 39 to mount the damper 40 for rotation within the passage 37 defined by the duct or scoop 36.

Referring now to FIGS. 3 and 4 there is illustrated the mechanism by which the damper or vane 40 is variably positioned within the passage 37 defined by the duct 36. In the FIG.'3 embodiment the position of the damper or vane 40 is controlled by a friction plate 44 which coacts with the side edge of the damper 40 to retain the damper in a fixed position. The friction plate 44 is mounted on the end wall 46. The vane 40 is provided with an opening 48 therethrough by means of which the vane 40 may be moved to various positions by using a screwdriver or similar tool to move the vane 40 to the desired position at which time it will be retained in that position by coaction between the edge of the vane 40 and the friction plate 44. To insure retention of the vane 40 in a preselected position the friction plate 44 may be provided with a plurality of dimples if desired.

In the embodiment illustrated in FIGS. 5, 6 and 7, instead of the friction plate 44 being secured to the side wall 46 to control the position of the damper or vane 40, a flexible spring clip 50 is bent at its upper end 51 to snugly and forcibly grip the edge of the vane 40 and is further provided with a plurality of serrations or bends designated 50a, 50b and 500 and terminates at its other end in a finger grip portion 52 which may be provided with a slot 54 in order that a tool such as a screwdriver can be used to reposition the vane in lieu of the fingers. The series of serrations or bends 50a, 50b and 500 serve to define three separate positions for the vane or damper 40. As illustrated in FIG. the spring clip coacts with the edge of the slot 38 at bend 50c and situates the vane 40 in its fully open position. In FIG. 6 the bend 50b is in contact with the edge of the slot 38 and positions the vane or damper 40 in a half open position. When the bend 50a is in contact with the edge of the slot 38 the damper will be retained in its fully closed position.

Air entering the luminaire cavity 24 through the slots and air return passages 37 may then be removed from the space 24 and drawn into the plenum space above the ceiling after removing heat from the light sources 28 through a plurality of conventional openings 56 in the top member 19.

The above described air return passage with its flow control facility provides, in an air return type of luminaire, an air return passage which is wholly situated on the door frame, will not interfere with the removal of lamps from the luminaire body when such change is necessitated, directs the air flow away from the center of the luminaire toward the end walls thus placing the cooling air adjacent the warmest portion of the lamps for purposes of heat removal, and although providing a smooth contour for the flow of air through the air passage, has none of such passage overlying the light transmissive portion of the door and therefore permits no shadow to be cast along the edge of the light transmissive member.

What is claimed is:

1. An air handling luminaire comprising: a troffer including a top wall and downwardly directed side and end walls defining a lamp cavity; means for operatively mounting a light source within said lamp cavity, door means closing off the bottom of said lamp cavity, said door means including a door frame and a light transmissive shielding media surrounded by said door frame; air handling slots in said door frame, at least one of said air handling slots having an air return passage connected thereto, said air return passage including a curved air return duct overlying said slot and directed outwardly of said door frame away from said shielding media, said curved air return duct constructed and arranged to shield light from the light source within said lamp cavity from said passage and direct return air toward the end walls of said troffer; and air flow control means mounted within said air passage to control the volume of air flowing through said passage; said air flow control means including a swingable vane mounted for rotation in said curved air return duct and further including a friction plate which coacts with the edge of said swingable vane for variably and selectively positioning said swingable vane within said air passage.

2. In an air handling luminaire which includes, a troffer having a top wall and downwardly directed side and end walls defining a lamp cavity; means for operatively mounting a light source within said lamp cavity; door means closing ofi the bottom of said lamp cavity, said door means including a door frame and a light transmissive shielding media surrounded by said door frame; the improved air return passage which includes, air handling slots in said door frame, at least one of said air handling slots having an air return duct connected thereto, said air return duct including a curved scoop overlying said slot and directed outwardly of said door frame away from said shielding media, said curved scoop constructed and arranged to shield light from the light source within said lamp cavity from said passage; and air flow control means mountedwithin said curved scoop to control the volume of air flowing through said air return passage; said air flow control means including a rotatable damper mounted for rotation in said curved air scoop and further including means in the form of a serrated spring clip connected to the edge of said damper and having a plurality of bends adapted to coact with a portion of said air return passage to selectively position said damper within said air passage to thereby control air flow therethrough.

I I I l 

1. An air handling luminaire comprising: a troffer including a top wall and downwardly directed side and end walls defining a lamp cavity; means for operatively mounting a light source within said lamp cavity, door means closing off the bottom of said lamp cavity, said door means including a door frame and a light transmissive shielding media surrounded by said door frame; air handling slots in said door frame, at least one of said air handling slots having an air return passage connected thereto, said air return passage including a curved air return duct overlying said slot and directed outwardly of said door frame away from said shielding media, said curved air return duct constructed and arranged to shield light from the light source within said lamp cavity from said passage and direct return air toward the end walls of said troffer; and air flow control means mounted within said air passage to control the volume of air flowing through said passage; said air flow control means including a swingable vane mounted for rotation in said curved air return duct and further including a friction plate which coacts with the edge of said swingable vane for variably and selectively positioning said swingable vane within said air passage.
 2. In an air handling luminaire which includes, a troffer having a top wall and downwardly directed side and end walls defining a lamp cavity; means for operatively mounting a light source within said lamp cavity; door means closing off the bottom of said lamp cavity, said door means including a door frame and a light transmissive shielding media surrounded by said door frame; the improved air return passage which includes, air handling slots in said door frame, at least one of said air handling slots having an air return duct connected thereto, said air return duct including a curved scoop overlying said slot and directed outwardly of said door frame away from said shielding media, said curved scoop constructed and arranged to shield light from the light source within said lamp cavity from said passage; and air flow control means mounted within said curved scoop to control the volume of air flowing through said air return passage; said air flow control means including a rotatable damper mounted for rotation in said curved air scoop and further including means in the form of a serrated spring clip connected to the edge of said damper and having a plurality of bends adapted to coact with a portion of said air return passage to selectively position said damper within said air passage to thereby control air flow therethrough. 